Electric lighting fixture with louver members



y 1954 G. J. TAYLOR ETAL 2,683,799

ELECTRIC LIGHTING FIXTURE WITH LOUVER MEMBERS Filed May 10, 1951 2Sheets-Sheet l FIG.2.

av /ram GEORGE J. TAYLOR LEO G. STAHLHUT G. J. TAYLOR ET AL July 13,1954 ELECTRIC LIGHTING FIXTURE WITH LOUVER MEMBERS 2 Sheets-Sheet 2Filed May 10, 1951 GEORGE J. TAYLOR LEO G. STAHLHUT MWM Patented July13, 1954 UNITED STATES PATENT OFFICE ELECTRIC LIGHTING FIXTURE WITHLOUVER MEMBERS Missouri Application May 10, 1951, Serial No. 225,556

8 Claims.

This invention relates to louvers or reflecting baffle means forelectric lighting fixtures, and has particular utility in connectionwith lighting fixtures of the overhead type for modifying the intensityof reflected light normally viewed from below the light fixture,

A principal object of the present invention is to provide a louver orbaille member for a lighting installation or light fixture which willeffectively control the direction and modify the brightness or intensityof reflected light coming from a lighting fixture located overhead.

It is also an object of this invention to provide a louver member of theabove character having a plurality of light reflecting surfaces disposedacross the plane of the louver and directed at varying angles so thateach of the light reflecting surfaces produces a variation in thedirection of the reflected light, thereby eliminating zones of highintensity light within the position at which the louver or bafile in alighting installation or fixture is normally viewed.

t is also an object of this invention to provide a light reflectinglouver or bafile member with a series of angularly related lightreflecting surfaces, wherein the angle imparted to each of thereflecting surfaces is predetermined by projecting segments of a curvedparabolical surface.

The invention consists in a lighting installation or in a fixture havinga frame provided with a light opening, a lamp or other source ofillumination, and a light reflecting louver or bafile member carried bythe frame in or adjacent the light source or lamps and acting to reflectlight from the lamp in modified directions, whereby to control thebrightness or intensity of the reflected light and thereby eliminateobjectionable zones of high brightness.

The invention also consists in the provision of a light reflectinglouver, particularly useful in connection with elongated fluorescentlighting fixtures, in which one or a plurality of such louvers may bedisposed within the fixture transversely of the lengthwise axis, forsoftening or modifying objectionable brightness or high intensityreflected light developed by such lighting fixtures, when arranged incontinuous rows or in spaced relation within ceiling recesses orsuspended from a ceiling and arranged in longitudinal relation.

The invention further consists in the parts and in the form and assemblyof such parts as will hereinafter be described in connection with theaccompanying drawings, wherein:

Fig. 1 is a transverse sectional elevational view of a fluorescentlighting fixture embodying the improved light reflecting louver member,

Fig. 2 is a fragmentary longitudinal sectional elevation taken at line2-2 of Fig. 1,

Fig. 3 is an enlarged fragmentary sectional elevation of a typical lightreflecting louver member shown in relation to a fluorescent lightingtube, the view constituting a fragmentary enlargement of the centralportion of the disclosure of Fig. 2;

Fig. 4 is a greatly enlarged sectional elevation of a light reflectinglouver member disclosing the arrangement and angular relation of theplurality of light reflecting surfaces formed in the member; and

Fig. 5 is a transverse sectional elevation of a modified lightingfixture.

On reference to Figs. 1 and 2, the lighting fixture, which has beenshown for purposes of disclosing the characteristics and features of thepresent invention, embodies a frame assembly A comprising a rectilinearhead structure it) for enclosing the circuit wiring and an attachedhousing in the form of a parabolic light reflector l I provided with alower flanged margin l2 in the plane of the light emitting opening 13.The light reflector housing I i encloses a spaced set of lamps I4 of thefluorescent tube type, these lamps being supported at their oppositeends by suitable brackets l5 mounted on the adjacent wall of the upperhousing [0.

The electric lighting fixture disclosed by Fig. 1 is provided with acentral longitudinal partition [6 of sheet material which has has beenformed to provide the opposite light reflecting walls ll. The walls I!constitute the inner parabolic light reflecting surface for cooperationwith the housing walls II. The partition it is attached to the adjacentwalls of the housing [0.

The light emanating from the opening l3 of the fixture A is subject tothe modifying effect of one or more louver members B secured in theframe transversely of the lengthwise axis thereof. Each louver has acentral notch 18 with inwardly projecting lugs Hi, all of which servesto releasably secure the louver in the partition #6 upon sliding thelouver into a transverse slot in the partition so that the lugs l9 fitinto openings therefor above the slot. In Fig. 2, a plurality of louvermembers B have been shown in sectional elevation to illustrate therelation of such louvers to the elongated fluorescent lamp or lightsource l4.

Each of the louver members B consists in an initially flat plate whichis formed of opaque material so as to reflect the light coming fromlamps M. The light reflecting louver members B, each have a plurality ofsimilar light reflecting surfaces 29 on both flat faces. Each of thelight reflecting faces 20 constitutes a segment of the louver facedirected or formed at an angle to the plane of the louver, so as toproduce a series of elongated surfaces from which the reflected lightmay travel in predetermined paths. The light reflecting surfaces 20 arearranged in a variable or progressive angular relation so that the faceof the louver is broken down into small light reflecting surfaces whichdiffuse the light and thereby avoid objectionable glare caused byconcentration of reflected light. Between each of these light reflectingsurfaces 2'6 there is located a relatively narrow connecting lightreflecting surface 2| having a different angular progression oninter-angular relation. The second series of surfaces 2| are disposed inangular positions opposite to that of the first described lightreflecting surfaces 2!].

With reference to Figs. 2 and 3 a light reflecting member B has beenselected at random along the length of the lamp Id, and the right handface thereof will be referred to in describing the light reflectingaction thereof. Itwill be observed that each of the first mentionedseries of light reflecting surfaces 20 has an angular position effectivefor directing light reflected therefrom downwardly through the lampopening l3.

The light reaching the reflecting surfaces is obtained from the lightsource it, substantially throughout that portion of its length presentedto the light reflecting member B, being considered. In connection withFig. 2, a number of points have been selected along the length of lampis for the purpose of further description. Such points are referred tohereinafter as light source points, from which all of the light is, forthe purpose of this discussion, considered to emanate.

If the light to be reflected by the louver member B is considered toemanate from lightsource point D, the filament of light D-ZU. impingingon any surface 20, as 20d, has an angle ofreflection which directs thelight sharply downwardly along the line D-2fl'. Different surfaces will,of course, result in different directions of reflection. Light filamentD-2l strikingv any of the surfaces 2i, as Zld, will reflect upwardlyalon the path designated by the line D-2l'. Light filament E-ZO frompoint E striking any surface 26, as 20c, reflects along the line E-ZO,and light filament E-Zl striking Surface 2le refleets along the lineE-2l. Light from point F is directed in a like manner, following lineF40 and reflecting along line F-Zfl'. The action of the alternate,angular surfaces 20 and 21 is to reflect light downwardly for directillumination and upwardly for indirect illumination. also apparent thatas the light source point in the lamp is moves farther away from thelouver B, or any other louver l3, the reflected light moves in pathswhich tend to approach the horizontal. This component of the totalreflected light is that which falls in the zone or area in which thefixture is normally viewed. However,

only a small quantity of light comes within this zone so that theintensity of the light does not reach objectionable values. selection ofa light point source closer tothe louver B can be shown to reflect lightmore into the areas which are overhead and not productive ofobjectionable glare or high intensity light. The beneficial resultobtained from this form of In like manner; the

light reflector louver is one of modified or dispersed reflected light,thereby eliminating the objectionable zones of brightness or highintensity light zones, heretofore found in connection with specularsurface louver members employed in a similar manner;

The foregoing objects and advantages are obtained by the use of a louvermember having a plurality of light reflecting surfaces plotted assegments of a parabolic curved surface. Therefore, the light reflectingsurfaces 29, formed as segments of a parabolic curved surface, have avariable angular relation across the face of the member for directingthe light through opening 13. In a similar manner, surfaces 2! aresegments of a parabolic curved surface, but the angular relation isopposite so that the light is directed away from opening l3.

This angular relation of surfaces 20 and 2! has been more particularlyshown in connection with Fig. 4 which illustrates a greatly enlargedfragmentary sectional elevation of a typical louver member B. Beginningat the lowermost edge 22- of the louver, it will be noted that the lightrefleeting surfaces 23 at the right hand face of the member have anacuteangular relation with the horizontal which progressively decreasesfrom the largest angle of 83 degrees at the lower margin 22 to thesmallest angular relation. The

opposite face of the same louver member is provided also with a similarseries of light reflecting surfaces having a similar progressivelyvariable angular relation.

As has been heretofore pointed out, the second series of lightreflecting surfaces 2| formed on the louver members B are disposed in anoppositely directed angular relation with the first mentioned surfaces.The surfaces 2| are given progressively increasing angles,- beginningwith the lowermost surface which makes an angle of- 36 degrees with thehorizontal. The second series of light reflecting surfaces 2| arealternately positioned with the first series ZO-thereof, whereby lightstriking such surfaces will be directedupwardly or away from the openingl3. In this manner, high intensity reflected light is further dispersedor broken up, but without affecting the desired degree of lightdelivered from-the-fix-' ture. Considering Fig. 2, it will be observedthat light emanating from point'D along line D-Zl and striking one ofthe light reflecting-surfaces 2| has an upwardly directed component oflight reflection which follows the line D-2l', as previously explained.

The example described in connection wlth Fig. 4 discloses specificangular relations for reflecting surfaces ZD-and 2|, but the form andconstruction of the louver B is not to be limited to the angles stated,as other angluar relations may long as the combined surfaces 20- or thecombined surfaces 2| fall on or approximate a parabolic curve.

In forming the presently improved light reflecting louver members B, astiff or rigidlouver can be obtained from material of minimum thickness,by staggering or alternating the position of the light reflectingsurfaces Ziland 2|. This alternating or staggering of the location oflight reflecting surfaces avoids-the formation, of local zones ofminimum thickness, thereby avoiding the danger of creating well definedzones of minimum thickness along which a fracture would be likely tooccur, should it be hit or subject to suddenshock.

While the present invention has been described in connection with a twolamp fluorescent lighting fixture, it should be understood that the samemay be employed in connection with a single lamp fixture formed byone-half of the structure disclosed in Fig. l, or in connection withother types of single or multi-lamp electric fixtures.

The advantages for the use of the presently described light reflectinglouver members may best be appreciated in connection with overheadfixture instaliations which, in large ofiices, engineering rooms, andfactory spaces are ordinarily disposed in continuous or closely spacedrows or lines, thereby creating objectionable streaks or bands ofreflected light which causes eye strain and work fatigue. The eye strainis produced by high intensity reflected light visible from below thelight fixture and in a zone to either side of the position substantiallyperpendicular to the surfaces of the transverse louvers. Accordingly,the presently improved louver members B disperse high intensityreflected light concentrations by varying the angles of reflection ofthe light coming from the lamp Hi. How this is accomplished has beendescribed in connection with the disclosure of the light source pointsD, E and F in Figs. 2 and 3, by way of example only. The effect ofvarying the angle of reflected light which issues through the opening 13is to soften the reflected light throughout the length of the rows oflight fixtures so that there are no objectionable high intensity lightspots or regions within the normal range of vision of persons viewingthe light fixtures from below and in working areas in and to each sideof a position normal to the plane of the transverse louvers B.

The lighting -fixture A (Fig. 1), shown by way of illustration, is of atype designed for mounting in a ceiling recess. The invention is notlimited thereto, as it is obviously possible to have a fixture,incorporating the louvers B, suspended below a ceiling to obtainincreased illumination by light reflected from the louvers upwardlythrough openings in the head structure lil. Such a fixture is shown inFig. 5, wherein the frame of the fixture is attached to a bracket 25suspending the fixture below the ceiling or other overhead surface. Thefixture is provided with a longitudinal head structure 2! enclosing thenecessary wires and supporting brackets 28 which carry the lamps orfluorescent tubes 29. The lower portion of head 2i is used to supportone or more louvers C which are similar to the louvers B, in that thelouvers C are provided with light reflecting surfaces at and iii whichare segments of a parabolic surface. Surfaces 36 are arranged to reflectlight downwardly from the fixture 25, while surfaces 3i are oppositelydirected to refleet light upwardly from the top of the fixture forindirect illuminating effects. In this fixture, the surfaces 3! of thelouver C are segments of a parabolic surface with its axis at an angleto the plane of the louver so that reflected light will not strike thesurfaces 36 and only a minimum of light will be intercepted by thelouver.

The foregoing description refers to certain preferred constructionswhich have been found to accomplish the objects of the invention.However, it should be clear that the lighting fixtures shown in thedrawing can be modified or changed according to mounting requirementsand style either of the fixtures selected or for the generalinstallation in a given room or area. It is also clear that the louverscan be made of any convenient material which will reflect light, andthat the material selected may be determined by the desired lightreflecting surface finish which can vary from the specular to thediffusive surfaces.

What we claim is:

1. A low brightness light reflecting louver comprising a flat plateformed to provide two series of light reflecting surfaces extendinglengthwise over each of the opposite faces thereof, the surfaces of oneseries in each face being oppositely annularly directed relative to thesurfaces of the other series in each face, and both series of surfacesin each face having angular relations with the plane of said flat platewhich vary from margin to margin over the width of said plate.

2. The louver set forth in claim 1, wherein one series of lightreflecting surfaces in each face has each surface thereof angularlyrelated with the plane of said plate to direct the light to one marginof the louver and the other series in each face has each surface thereofangularly related with the plane of said plate to direct the light tothe opposite margin of the louver.

3. An electric lighting fixture comprising a frame, a lamp supported insaid frame, and a light reflecting member formed from a flat plate andbeing disposed adjacent said lamp, said member having two series oflight reflecting surfaces on each face thereof extending lengthwise ofthe same, the surfaces of one series in each face of said member beingoppositely angularly directed relative to the surfaces of the otherseries in each face of the member, and both series of surfaces in eachface of the member having angular relations with the plane of saidreflecting member which vary over the width of said member, one seriesof surfaces in each face of the reflecting member being angularlypresented to said lamp for modifying the direction of the reflectedlight passing outwardly of said frame, and the other series ofreflecting surfaces in each face of the reflecting member reflectinglight back toward said lamp. I

4. An electric lighting fixture as set forth in claim 3, wherein thelight reflecting surfaces on one face of the reflecting member arestaggered relative to the light reflecting surfaces on the opposite faceof said reflecting member.

5. An electric lighting fixture comprising an elongated frame, afluorescent lamp in said frame, and a plurality of light reflectinglouver members vertically disposed in said frame transversely of theelongated frame, each of said members having in each face thereof twoseries of angularly related light reflecting surfaces extendinglengthwise thereof and transversely of the frame, the surfaces of oneseries in each face of each of said members being oppositely angularlydirected relative to the otherseries of sur faces in each face of themember, and both series of surfaces in each face of each member havingangular relations with the plane of the reflecting member which varyover the width of the member, said reflecting surfaces constitutingsegments of a parabolic surface presented to said lamp for angularlyvarying the direction of the light reflected therefrom across thevertical width of and viewed from below said members.

6. A low brightness light reflecting louver com prising a flat plateformed to provide two series of light reflecting surfaces extendinglengthwise over each of the opposite faces thereof, the surfaces of oneseries in each face being oppositely angularly directed. relative to thesurfaces of the other series in each face, and both series of surfacesin each face having angular relations with the plane of said flat platewhich vary across the width of said plate.

7. A low brightness light reflecting baffle comprising a generally flatelongated and opaque plate formed with two series of light reflectingsurfaces in its opposite faces; the two series of reflecting surfaces ineach face of said baflle being arranged in alternating relation acrossthe width of said bafile and being alternately oppositely angularlydirected relative to the plane of the face of the bafile, and said twoseries of surfaces in each face being further arranged in staggeredrelation with respect to the two series of surfaces in the opposite faceof the plate. with all of said series of reflecting surfaces havingangles which vary progressively across the width of said bafile.

8. A low brightness light reflecting louver comprising an elongatednarrow flat plate formed to provide two series of light reflectingsurfaces 8 extending uninterruptedly lengthwise of and substantiallythroughout the length of one face of said plate, the surfaces of oneseries being oppositely angularly directed relative to the surfaces ofthe other series, and both series of surfaces having angular relationswith the plane of said face which vary across the width of said face.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,535,985 Clark Apr. 28, 1925 2,242,872 Rolph May 20, 19412,411,952 Biller Dec. 3, 1946 FOREIGN PATENTS Number Country Date531,611 France Oct. 2'7, 1921 OTHER REFERENCES The Magazine of Light(page 8), Nov. 25, 1940.

